Archive for May, 2011

High Latitude Blocking Over The NW Territories Combined with Long Wave Ridging North Of Hawaii Will Keep The Upper Jet Suppressed Into Northern Ca In The Mean

Yes…we still are being effect by a blocking pattern. The positive height anomaly north of Hawaii combined with above normal heights over the Northwest Territories will keep the upper jet stream in the mean suppressed over Northern Ca. That means that Central Ca will be subjected to periods of unsettled weather with periods of nice weather too! Today is an example of nice weather with highs in Mammoth expected near 60 degrees by afternoon. However, the short wave upper ridge responsible for the nice day will translate east tonight giving way to another chilly air-mass that will mainly effect Northern Ca as far as precip and much cooler than normal temps.

 For Wednesday…..an upper trof will move through our area bringing another windy period with showers possible Wed afternoon and some light snowfall Wednesday night. The models still show the possibility of at least a moderate wind event Wednesday afternoon. The new Tuesday 12z WRF has the strongest gradient from Central Mono County south through the Owens Valley. The Owens Valley may really get hammered by strong down-sloping winds during the late afternoon and into the Evening hours Wednesday. The NWS has hoisted High Wind Watches for both Mono and the Owens Valley for Wednesday afternoon and night. 

As far as the upper elevations….700mb winds peak about 45 to 50knots, so sierra crest winds will gust 90 to 100mph late Wednesday afternoon. The FROPA will occur during the early evening hours over Mono County. Some light snow is possibly Wednesday night with a dusting possible as the snow level drops to 6500 feet.

FIRST LOOK AT HOLIDAY WEEKEND:

The weather over the weekend is still “without” a lot of confidence. The American models (GFS) has the weather much milder then the ECMWF. Looking at this mornings GFS Ensembles from the 00z Tues run…the HT 500 mean heights are around 570dm in a cyclonically curved flow indicating that the weather may be breezy….cooler then normal but dry. The lowest heights in the trof over the far west is over Washington State. By Sunday, the jet does drop south with unsettled weather returning. 

The ECMWF is a different bird. It has HT500 heights in its ensemble of 564dm….capable of showery, breezy weather for Mammoth. Air-mass temps would be some 6 degrees cooler and with the potential of more cloud cover, so it could be an additional 5+degrees cooler as well. The ECMWF has this positive tilt chilly trof plunging south through California through Sunday afternoon and it could be quite active. The trend of the ECMWF has the long wave trof reloading early the following week with a cold snow producing system sweeping through Mammoth the very end of the month.  The GFS is much weaker with that trof.

Energy still coming off Japan:

In using Hovmoller’s Western Pacific surface cyclogenesis studies, the first cyclonically curved isobar crosses 140east on the 27th of May. The important issue is, that this system really bombs out. Thus….there is some serious support in the Dweebs estimation for the Tuesday/Wednesday storm a week away. 

Stay Tuned to see how this all works out!!

Dr Howard and the Dweebs………………………..:-)

 

 

 

 


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Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.

Another 8.5 inches fell upon Mammoth Mt over night…..Snow showers possible today with highs in the 30s…..Warmest day this week to be Friday with a chance of showers returning this weekend……Models beginning to trend milder by Holiday Weekend?

Latest RAMSIS showing that most of the action has shifted into the Southern Sierra this morning. However, there is still quite a bit of showers over Western Nevada. Looking a the heights/vorticity from this mornings WRF, there are still a couple of vort centers that have to clear the state today and with the flow backing to the NE later tonight….showers a good bet today with even some up-slope showers tonight into Thursday Am possible. The Dweebs do not expect any more then an inch or two max. It’s cold today with highs in the 30s then 40s Thursday. Friday will be in the upper 50s. The weekend looks cooler then normal with some showers possible Saturday into Monday, but not nearly as cold as it has been.

Longer Range Ponderings……

What is consistent in the global models is that they all keep at least some blocking over northwest North America from this mornings runs. This  usually implies a suppressed jet into the west coast for sometime. However, some of the models are retrograding the central pacific upper ridge  to the western pacific later next week which would tend to ridge us up.  MJO dynamic models not much help. It is likely that clearity will return by the early next week for the following weekend.


Dr Howard and the Dweebs………………………..:-)


THE MISSING LINK?

A new paper recently released from Scientists at AARHUS University proves a cosmic ray/cloud link. The more cloud cover covering the world the lower the global temperatures and vice versa. The amount of particles reaching the earth is partly controlled by solar activity and is very important to climate modeling.


SEE LINK BELOW:

http://science.au.dk/en/news-and-events/news-article/artikel/forskere-fra-au-og-dtu-viser-at-partikler-fra-rummet-skaber-skydaekke/

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Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.

Snow developing later this evening with heavy snow after midnight…another foot possible over the crest by Wednesday pm…..Break Thursday and Friday then more unsettled weather this weekend…..

Well its the middle of May and the Dweebs are always thinking about weather and climate. Although, snow in the month of May is not unusual here in Mammoth, and in fact happens in most years, the persistence of cooler then normal temps is. Just look at the snow pack for this time of the year. It is still at least 150% of normal. The roads in the lakes basin and down to Reds meadow is probably with still 7 to 10 feet over the top and it is likely that the road over Tioga will not open until well into June.  There are the reports of 75 foot snowpacks covering roads in the mountain areas of the pacific northwest.  Must be Global Warming?  😉

Blame it on the negative PDO and a very slow awaking Sun from a long hibernation.

The negitive phase of the pacific decadial oscillation (PDO) is going strong and if history repeats itself may continue more on then off for the next 20 to 30 years. That means that the SSTs over the eastern pacific are colder then normal and that the west should have more precipitation and colder WX in the years to come. Summer may tend to be cooler and winters earlier and longer. El Ninos will tend to be weaker or shorter lived. If you want to get an idea of the weather for a negative PDO just study the weather of the 1930s, 40s and 50s here in this country. Watch La Nina this year. It is currently weakening and should pretty much be gone by Summer. However, watch and see if it does not return this Fall!

Current Discussion:

Active pattern to continue through Wednesday.  A Cold/wet upper low with a 130knot upper jet will cut through Central Ca  through tomorrow.

The position of the upper jet is west northwest and the axis just south of Mammoth. Good for divergence aloft in the front left quad over Mammoth.  Although the second impulse fizzled last night, the next one or the 3rd in the series will bring heavy snowfall after midnight tonight into Wednesday morning, with several inches accumulation on our local roads, especially above 8000 feet. Over a foot of new is possible over the crest by Wed PM.

Unstable air aloft with warming surfaces will allow a few afternoon convective showers to develop each afternoon Thursday and Friday…then a new negative trof digs in Saturday with more unsettled weather through Monday. 

When will it end?  When will warm weather return to the high country for an extended visit?

It is the Dweebs opinion that track of MJO will play an important part in the pattern across the Pacific and the west coast. The problem is that the forecast from NCEP is for the MJO to circle back from its current position in Phase 8 into phase 7 during the last week of May. However, the ECMWF does not agree as it progresses MJO through phase 8 as it weekens it rapidly.  Hopfully by the end of this week they will become more in agreement.  For whatever it is worth the 8 to 14 days outlooks do build a ridge into California by the end of the month. However, this possibility is probably unlikely, as based upon persistence, and the NCEP MJO model, the Dweebs feel that the storm machine will probably keep right on cranking into June.


The Dweeber………………….:-)


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Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.